Improve compatibility with other operating systems

[swissspidy]

I'm trying to improve Windows support a little bit so that tests could run on CI. Doing things in PHP vs. CLI commands is one step.

Lots of AI code changes in here, might need some cleanup

Main change is blocked by wp-cli/wp-cli#6124

To-do:

• Add Behat tags to skip tests for certain OS?

See #155

[swissspidy]

Looks like there's basically two categories of remaining testing errors on Windows:

• When doing things like echo "value1", it will actually add the quotes to stdout.
• Line ending issues in Test CSV containing with headers scenario